HVAC Guide Specifications

Commercial Hydronic Cassette Fan Coil

Size Range:

¾ to 3 Tons

7,000 to 36,000 Btuh, Nominal Cooling

15,000 to 66,000 Btuh, Nominal Heating

Carrier Model Number:

42WKN

Part 1 — General

1.01 SYSTEM DESCRIPTION

Indoor, in-the-ceiling mounted, chilled or hot water coil, to be matched with a commercial chiller, water source heat pumps, or hot water boiler (180 F maximum).

1.02 QUALITY ASSURANCE

Base unit shall be certified by UL (Underwriters Laboratories). Each coil shall be factory tested for leakage at 325 psig air pressure with coil submerged in water. Insulation and adhesive shall meet NFPA-90A (National Fire Protection Association) requirements for flame spread and smoke generation. Insulation shall be rated to UL94 VO. All equipment wiring shall comply with NEC (National Electrical Code) requirements.

1.03 DELIVERY, STORAGE, AND HANDLING

Unit shall be stored and handled per manufacturer’s instructions.

1.04 WARRANTY (One year on parts).

Part 2 — Products

2.01 EQUIPMENT

A. General:

Indoor, downward discharge 2 or 4-pipe low-profile in-ceiling fan coil. Units shall come complete with cooling coil or hot water coil (4-pipe systems only), fan, fan motor, piping connectors, electrical controls, condensate pump, and hanging brackets.

B. Unit Cabinet:

1. Cabinet shall be constructed of galvanized sheet steel. Cabinet shall have filter tracks and cleanable filters which shall be accessible from below. Adjacent room cooling to be provided by a simpleknockout in the cabinet side panel, and cabinet shall have provisions to accommodate a limited amount of ductwork, if desired.

2. Fan shall be a centrifugal, direct-drive blower type with air intake in center of the unit and discharge on the perimeter. Air louvers shall be adjustable for 2, 3 or 4-way discharge. Air outlet vanes shall be fully insulated aluminum to prevent condensation from forming. Vanes shall be manually adjustable on unit sizes 08,12, but shall be driven by an electric motorfor unit sizes 18-36.

3. Fascia shall be constructed of high impact polystyrene.

C. Coil:

1. Standard base unit shall be equipped with a cooling coil for installation in a 2-pipe system. Additional coil depth and circuiting shall be provided for installation in a 4-pipe system.

2. Heating coils are single row, independently circuited coils specifically designed for hot water application. Heating coil is located downstream from cooling coil.

3. Coils shall have ½-in. copper tubes, aluminum fins bonded to the tubes by mechanical expansion, and a working pressure of 325 psig.

4. Each coil shall have a manual air vent on upper connection, a drain port on the lower connection.

D. Motors:

Motor shall be enclosed and with thermal overload protection, sealed for life lubricated bearings, and external rotor allowing good heat dissipation. Fan motor shall be 3-speed.

E. Controls:

Controls shall be 24-v, and shall be easily operated by the user from a wall-mounted thermostat. A normally closed float control shall be in the condensate sump to shut unit down in case of pump malfunction.

F. Alarm Interlock Relay:

Alarm interlock relay shall include a relay for unit failure notification. Normally open/normally closed contacts are available for field connection.

G. Filters:

Unit shall have a filter track with factory-supplied cleanable filters or MERV 8 disposable filters.

H. Electrical Requirements:

Unit shall operate on a 115-v, 208-v, 230-v or 277-v 60 Hz power supply or on 110-v or 220-v 50 Hz power supply as specified on the equipment schedule.

I. Operating Characteristics:

A one-coil unit installed in a 2-pipe system shall be capable of providing cooling as specified by the operating mode of the central water supply system. A double-circuit coil unit installed in a 4-pipe system shall be capable of providing sequenced heating and cooling.

J. Special Features:

1. Fresh Air Intake Kit:

The fresh air intake kit shall include duct collars for connection to the unit.

2. Duct Collars:

Duct collars shall be available to allow connectionof a 5 in. or 6 in. (depending on unit size) flexible duct to the cassette.

3. Thermostat:

The thermostat shall be commercial grade to control unit operation and shall provide single speed fan capability. Automatic changeover from cooling or heating shall be provided (4-pipe systems only).

4. Motorized Valve Accessory:

The motorized valve shall be a two-position, spring return two or three-way valve.

5. Microprocessor Control:

a. The microprocessor control shall include a custom designed microprocessor fitted to the cassette to enable room conditions to be maintained at a user defined set point.

b. Microprocessor controller shall allow automatic control of fan speed based on demand in space. The controller, either an infrared transmitter or pendant transmitter, also allows programming of a weekly operating schedule.

6. Electric Heat:

Single-stage electric heat shall include fitted heating elements manufactured for maximum surface area and lower working temperature for improved reliability. Thermal cutout protection switches are fitted to the electric heat circuit to protect against overheating. The optional electric heating elements are available with the 208/220/230-v model units only.

7. Hot Water Coil Freeze Protection Sensor:

The freeze protection sensor shall be available for mounting to prevent freezing of the hot water coil assembly. When the sensor detects a freeze up condition, it will force the flow control valve open and prevent the unit fan(s) from running.

8. Disconnect Switch:

The non-fused disconnect switch shall be factory mounted on the exterior of the control panel and sized for the full load amperage of the unit to enable the unit to be disconnected from the power supply prior to any maintenance.

9. Shroud:

A shroud shall be available as a sheet metal cover used to cover unit housing when the unit is not mounted in a drop or false ceiling. The shroud is painted Sky White with a hammer-tone finish.

10. Wall-Mounted Pendant:

A wired, wall-mounted pendant for communicationto the microprocessor controller shall be available to replace the standard infrared remote control.

11. Aquastat:

An aquastat shall be available for use with a 2-pipe heating/cooling changeover system.